As shown in the prior art, the conventional spring and shock absorber system is used in automobiles to reduce shock or concussion when the vehicle strikes a bump or, in general, when the wheel movement of the vehicle over a roughness in the surface of the road moves the auto's axle toward the frame or body of the vehicle. The shock absorber is mounted between the automobile frame and the axles. It usually consists of a piston and dampening means inside a fluid-filled cylinder. When the wheel hits the bump, instead of the axle communicating the shock directly to the automobile frame, the piston is pushed upwardly or downwardly as in FIGS. 2A-2D and the fluid in the specially-designed cylinder, with or without additional shock dampening means, resists and decelerates the movement of the piston thus offsetting the force of the bump. The hydraulic fluid, rather than the frame, absorbs most of the shock. The ease with which the piston can compress the fluid determines the so-called "hardness" of the ride.
When a vehicle turns around a curve in the road, the suspension permits the vehicle body to rotate slightly about its longitudinal axis in response to the rolling force exerted on the body during the turn. Typically, vehicle passengers experience this effect as a tilt of the vehicle body, with the side of the body on the outside of the curve being relatively lower than the side of the body on the inside. Further, the vehicle body tends to pitch forward so that the front of the body is relatively lower than the rear. The pitch and roll combine to incline the vehicle body toward the front corner on the outside of the turn.
The prior art is replete with anti-roll systems that may be added to the conventional shock absorber systems. In general, these systems are complex requiring several additional pieces of equipment in a space that is already crowded. These systems counteract vehicle roll by providing lifting forces acting between the vehicle body and the axle or suspension on the outside of the curve or by providing a vehicle lowering force acting between the body and axle or suspension on the inside turn side of the vehicle. Some anti-roll systems in the prior art provide complementary lifting and lowering forces on both sides of the vehicle simultaneously with the accompanying array of equipment.
A typical tilt or sway control apparatus is shown in U.S. Pat. No. 2,934,353 issued in 1960 to L. B. d'Avigdor. In this apparatus, the inventor provides at each side of the vehicle, between the axle and the body, a body raising and lowering motor device including an expandable pneumatic chamber and means for supplying air to and discharging it from the chamber to regulate the volume of the chamber. This air supply and exhaust means is controlled by electrically operated valves in response to an electrically operated switch mechanism. The switch mechanism responds to centrifugal force and to gravity, and is thus affected by both tilting and lateral acceleration of the vehicle.
It is an object of the present invention to provide an improved tilt control apparatus, improved over the prior art in both effectiveness and in simplicity.
It is a further object to provide such apparatus that will not affect the vehicle body when the vehicle is subjected to roughness in the road, i.e. an apparatus that will not interfere with the vehicle's conventional shock absorber system.
It is still further object to also provide means for tilt control by modification of the vehicle's conventional shock absorber system.
Because of the large force generated by the tilt of the heavy vehicle, a strong support structure is necessary at the frame and at the axle for tilt control. Since the conventional shock absorbers in existing vehicles are usually placed in the strongest areas, it is also an object of this invention to incorporate the tilt-controller into the shock absorber systems currently in use, which will permit easy insertion into existing vehicles. Other objects will be apparent hereinafter.